The present invention relates to a semiconductor device, a method of manufacturing the same, a circuit board and an electronic instrument.
In the case of mounting a semiconductor chip face down on a substrate, the semiconductor chip can be firmly fixed on the substrate by an adhesive. Since the thermal expansion coefficient of the adhesive is larger than that of the semiconductor element, there may be strip off between the semiconductor element and the adhesive. In order to reduce the difference in the thermal expansion coefficient, an insulating filler such as a silica-based filler which is smaller than a binder (or a resin) in the thermal expansion coefficient may be put in the adhesive.
However, if a bump having a height larger than a predetermined value is used as shown in FIG. 11, it may occur that the shape of a bump 402 is deformed to have a relatively large recess 404 in an end surface in a process of pressing a semiconductor chip 400 against a substrate 420 through an adhesive 410 containing an insulating filler 412. It has been found from experimental results that a force applied to the end surface of the bump 402 from the adhesive 410 is increased since the adhesive 410 containing an insulating filler 412 such as a silica-based filler has low fluidity and high viscosity. The bump 402 is easy to deform when its height is large (e.g. when a small load is applied for leveling), and the deformation of the bump starts before the bump passes through the adhesive 410 and is electrically connected to an interconnecting pattern 422 of the substrate 420. As a result, the recess 404 is formed in the end surface of the bump 402 facing the interconnecting pattern 422 of the substrate 420.
As shown in FIG. 11, if the recess 404 is formed in the end surface of the bump 402, an insulating binder (or resin) or the filler 412 readily gathers in the recess 404. The electrical connection between the bump 402 and the interconnecting pattern 422 is affected by these insulating binder (or resin) and filler 412. However, there has been a difficulty in controlling the insulating filler 412.